I'm studying how the FTP protocall works in vb.net. The client side is more than well documented and very easy to follow, however I cant find anything on building an FTP server....Maybe there is no such thing as a virtual FTP server?
I did manage to find some document online which sends files back and forth but its not an actual FTP server (rather a clever way of mimicking one).
the client side code bellow clearly states FTPWebRequests and also clearly makes a connection to an FTP server ussing a password and username... its my probable understanding a means of creating a virtual FTP server also then exists?
Imports System.IO
Imports System.Net
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
'Create Request To Download File'
Dim wrDownload As FtpWebRequest = WebRequest.Create("ftp://ftp.test.com/file.txt")
'Specify That You Want To Download A File'
wrDownload.Method = WebRequestMethods.Ftp.DownloadFile
'Specify Username & Password'
wrDownload.Credentials = New NetworkCredential("user", "password")
'Response Object'
Dim rDownloadResponse As FtpWebResponse = wrDownload.GetResponse()
'Incoming File Stream'
Dim strFileStream As Stream = rDownloadResponse.GetResponseStream()
'Read File Stream Data'
Dim srFile As StreamReader = New StreamReader(strFileStream)
Console.WriteLine(srFile.ReadToEnd())
'Show Status Of Download'
Console.WriteLine("Download Complete, status {0}", rDownloadResponse.StatusDescription)
srFile.Close() 'Close
rDownloadResponse.Close()
End Sub
Related
Ok so, basically i want to connect an access database (.mdb file) to my project. Now yes i have indeed connected it through the "data origin" wizard but the problem is that when i transfer the exe AND the database to another pc, it doesn't find it (obviously).
Dim appPath As String = My.Application.Info.DirectoryPath
Dim txtconnesione As String = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & appPath & "\Magazzino.mdb"
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Me.TableMagazzinoBindingSource.DataSource = txtconnesione
Me.TableMagazzinoTableAdapter.Fill(Me.MagazzinoDataSet.TableMagazzino)
End Sub
appPath is basically where the program gets started.
With this code it actually shows me the whole grid but it's empty, just like this:
i didn't used a connection string and i didn't copy it in the project (sorry for bad english, if you don't understand i'll try to explain better)
I created a Visual Studio 2019 project that uses FileSystem.FileExists and both StreamWriter and StreamReader
I also created a folder named Resource with the intention of creating a txt file in this folder
Knowing I need to tell the Writer and Reader where to find the file I used these lines of code
Dim path As String = "C:/Users/Me/source/repos/TestForms/TestForms/Resource/"
If Not My.Computer.FileSystem.FileExists(path & "Check.txt") Then
Because I do not full understand how to deal with a SQLite database yet lets say I put the database in the folder Resource. And if I make a EXE package that will run on another computer that string path is by my best guess is not going to work
In the process of leaning I keep seeing this line of code. I see no path to the database
m_dbConnection = New SQLiteConnection("Data Source=MyDatabase.sqlite; Version=3;")
Granted I am dealing with a txt file now but if it was a SQLite database file
My Question is how does the connection know where the database is ?
I also need to import this reference Imports System.IO
Coming from NetBeans I got spoiled with Auto Import
Second Question Does VS 2019 not have an Auto Import feature?
I am adding a screen shot of Solution Explore
Tried to add Resource folder to Resources that did not work real well
Stream Reader Code below without error
Private Sub btnRead_Click(sender As Object, e As EventArgs) Handles btnRead.Click
readDATA()
End Sub
Private Sub readDATA()
Dim line As String
Using reader As New StreamReader(path & "Check.txt", True)
line = reader.ReadToEnd.Trim
tbHaveOne.Text = line
End Using
End Sub
Code that creates Check.txt
Private Sub frmThree_Load(sender As Object, e As EventArgs) Handles MyBase.Load
haveFILE()
'tbHaveTwo.Text = frmOne.vR'KEEP see frmOne
'tbHaveOne.Select()
End Sub
Public Sub haveFILE()
'If My.Computer.FileSystem.FileExists(path & "Check.txt") Then
' MsgBox("File found.")
'Else
' MsgBox("File not found.")
'End If
If Not My.Computer.FileSystem.FileExists(path & "Check.txt") Then
' Create or overwrite the file.
Dim fs As FileStream = File.Create(path & "Check.txt")
fs.Close()
tbHaveTwo.Text = "File Created"
tbHaveOne.Select()
Else
tbHaveTwo.Text = "File Found"
tbHaveOne.Select()
End If
End Sub
You should pretty much never be hard-coding absolute paths. If you want to refer to a path under the program folder then you use Application.StartupPath as the root and a relative path, e.g.
Dim filePath = Path.Combine(Application.StartupPath, "Resource\Check.txt")
Then it doesn't matter where you run your program from. For other standard folder paths, you should use Environment.GetFolderPath or My.Computer.FileSystem.SpecialDirectories. For non-standard paths, you should let the user choose with a FolderBrowserDialog, OpenFileDialog or SaveFileDialog and then, if appropriate, save that path to a setting or the like.
When it comes to database connection strings, some ADO.NET providers support the use of "|DataDirectory|" in the path of a data file and that gets replaced at run time. What it gets replaced with depends on the type of app and how it was deployed. For Web Forms apps, it resolves to the App_Data folder. For ClickOnce Windows apps it resolves to a dedicated data folder. For other Windows apps, it resolves to the program folder, just like Application.StartupPath. I think the SQLite provider supports it but I'm not 100% sure. If it does, you could use something like this:
m_dbConnection = New SQLiteConnection("Data Source=|DataDirectory|\Resource\MyDatabase.sqlite; Version=3;")
EDIT:
If you add data files to your project in the Solution Explorer and you want those to be part of the deployed application then you need to configure them to make that happen. Select the file in the Solution Explorer and then set the Build Action to Content and the Copy to Output Directory property to Copy Always or, if you intend to make changes to the file when the app is running, Copy if Newer.
When you build, that file will then be copied from your project source folder to the output folder along with the EXE. You can then access it using Application.StartupPath at run time. That means while debugging as well as after deployment, because it will be copied to the "\bin\Release" output folder as well as the "\bin\Debug" output folder. If you add the file to a folder in the Solution Explorer, that file will be copied to, hence the reason I said earlier to use this:
Dim filePath = Path.Combine(Application.StartupPath, "Resource\Check.txt")
Here is the working code to Create a Text file if it does not exist and if it does exist the user is notified.
We also were able to Write & Read from the Text file
One of the disappointments is we were not able to use StreamReader
We did solve this error where the file name was created like this "Check.txtCheck.txt This line of code below created the File this way in the folder Bin > Debug
If Not My.Computer.FileSystem.FileExists(filePath & "Check.txt") Then See Code for correct format
One other BIG lesson Do NOT create a folder and place your Text file in that folder
I am not sure using the code "Using" was a good idea further research needed on that issue
Working Code Below
Private Sub frmThree_Load(sender As Object, e As EventArgs) Handles MyBase.Load
haveFILE()
End Sub
Public Sub haveFILE()
If Not System.IO.File.Exists(filePath) Then
System.IO.File.Create(filePath).Dispose()
tbHaveTwo.Text = "File Created"
tbHaveOne.Select()
Else
My.Computer.FileSystem.FileExists(filePath) ' Then
tbHaveTwo.Text = "File Found"
tbHaveOne.Select()
End If
'This line of code created the File this was in the Bin > Debug folder Check.txtCheck.txt
'If Not My.Computer.FileSystem.FileExists(filePath & "Check.txt") Then
End Sub
Sub PlaySystemSound()
My.Computer.Audio.PlaySystemSound(
System.Media.SystemSounds.Hand)
End Sub
Private Sub btnWrite_Click(sender As Object, e As EventArgs) Handles btnWrite.Click
If tbHaveOne.Text = "" Then
PlaySystemSound()
'MsgBox("Please enter a username.", vbOKOnly, "Required Data")
'If MsgBoxResult.Ok Then
' Return
'End If
Const Title As String = "To EXIT Click OK"
Const Style = vbQuestion
Const Msg As String = "Enter Data" + vbCrLf + vbNewLine + "Then Write Data"
Dim result = MsgBox(Msg, Style, Title)
If result = vbOK Then
'MsgBox("Enter Data")
tbHaveOne.Select()
Return
End If
End If
writeDATA()
End Sub
Private Sub writeDATA()
Dim file As System.IO.StreamWriter
file = My.Computer.FileSystem.OpenTextFileWriter(filePath, True)
file.WriteLine(tbHaveOne.Text)
file.Close()
tbHaveOne.Clear()
tbHaveTwo.Text = "Data Written"
End Sub
Private Sub btnRead_Click(sender As Object, e As EventArgs) Handles btnRead.Click
readDATA()
End Sub
Public Sub readDATA()
Dim fileReader As String
fileReader = My.Computer.FileSystem.ReadAllText(filePath)
tbHaveOne.Text = fileReader
End Sub
I've written a Windows-based TCP server program based on some VB code I found on the internet several years ago (I can't find the link now, but it was called "multi-client server program" or something like that).
The server communicates with a couple of Enterprise iPhone client apps that I have also developed. I've successfully incorporated this code into two separate server programs that work just fine on both the development server and the production server. I'm working on a third iOS client application and a corresponding server program, which works fine on the development machine, but will not work on the production server -- the same machine that hosts the other two server programs with no problem.
It was working for a while, but as I have added more functionality to the server class, it seems to have stopped processing the incoming data, but only on the production machine.
The code that performs the connection functions is contained in a separate public class which is supposed to communicate with the Windows form that processes the incoming data. Using msgbox's for debugging tools, I have been able to confirm that the Client Connection class is connecting and is receiving the data, but it for some reason will not communicate that data with the Windows form.
My only thought is that it must be a threading issue, but I am not sure, and I have no idea how to find out.
To recap, just to be clear:
The code works fine on the development server, but not on the production server.
The client connection class is identical in every way with the other two working server programs.
That the client is communicating with the client connection class has been confirmed. The incoming data can be captured inside the connection class and displayed in msgbox's, so the data is getting through.
The Windows class that processes the incoming data is not receiving the data from the public client connection class.
EDIT: I should have included this in the original post: The development server is Win 7; the production sever is Windows Server 2012.
Because of the complexity of this code, I am not sure what snippets would be applicable for this, but I'll do my best to include what makes most sense to me here.
This is the entirety of the client connection class with the exception of the method that sends outgoing data. Again, this was copied from a website several years ago, and the comments are those of the original developer:
Imports System.IO
Imports System.Net.Sockets
Imports System.Data.SqlClient
Public Class ConnectedClient
Private cli As TcpClient 'declare a tcp client which will be the client that we assign to an instance of this class
Private uniqueid As String 'this will be used for the name property
Dim strErrorLogPath As String
Public Property name ''This will be the name of the ID containing its Unique ID
Get
Return uniqueid 'when we want to get it, it will return the Unique ID
End Get
Set(ByVal value)
uniqueid = value 'Used for setting the name
End Set
End Property
Sub New(ByVal client As TcpClient)
Dim r As New Random 'create a new random to serve as way to create our unique ID
Dim x As String = String.Empty 'declare a new variable to hold the ID
For i = 0 To 7 'we are going to have an ID of 7 randomly generated characters
x &= Chr(r.Next(65, 89)) 'create a generate dnumber between 65 and 89 and get the letter that has the same ascii value (A-Z)
' and add it onto the ID string
Next
Me.name = client.Client.RemoteEndPoint.ToString().Remove(client.Client.RemoteEndPoint.ToString().LastIndexOf(":")) & " - " & x 'set the name to the Unique ID
cli = client 'assign the client specified to the TCP client variable to we can operate with it
cli.GetStream.BeginRead(New Byte() {0}, 0, 0, AddressOf read, Nothing) 'start reading using the read subroutine
End Sub
Public Event gotmessage(ByVal message As String, ByVal client As ConnectedClient) 'this is raised when we get a message from the client
Public Event disconnected(ByVal client As ConnectedClient) 'this is raised when the client disconnects
Sub read(ByVal ar As IAsyncResult) 'this will process all messages being received
'bn-note: This is the entry point of the data being received from the client.
Try
Dim sr As New StreamReader(cli.GetStream) 'initialize a new streamreader which will read from the client's stream
Dim msg As String = sr.ReadLine() 'create a new variable which will be used to hold the message being read
If msg = "" Then
RaiseEvent disconnected(Me) 'WE CAN ASSUME THE CLIENT HAS DISCONNECTED
Exit Try
'msg = "Null Message"
End If
WriteToRawIncomingDataLog(msg)
RaiseEvent gotmessage(msg, Me) 'tell the server a message has been received. Me is passed as an argument which represents
' the current client which it has received the message from to perform any client specific
' tasks if needed
cli.GetStream.BeginRead(New Byte() {0}, 0, 0, AddressOf read, Nothing) 'continue reading from the stream
'End Ifz
'Catch ex As System.NullReferenceException
Catch ex As Exception
Try 'if an error occurs in the reading purpose, we will try to read again to see if we still can read
Dim sr As New StreamReader(cli.GetStream) 'initialize a new streamreader which will read from the client's stream
Dim msg As String = sr.ReadLine() 'create a new variable which will be used to hold the message being read
WriteToRawIncomingDataLog(msg)
RaiseEvent gotmessage(msg, Me) 'tell the server a message has been received. Me is passed as an argument which represents
' the current client which it has received the message from to perform any client specific
' tasks if needed
cli.GetStream.BeginRead(New Byte() {0}, 0, 0, AddressOf read, Nothing) 'continue reading from the stream
'End If
'Catch ex2 As System.NullReferenceException
' Stop
Catch ' IF WE STILL CANNOT READ
RaiseEvent disconnected(Me) 'WE CAN ASSUME THE CLIENT HAS DISCONNECTED
End Try
End Try
End Sub
Here is the Windows form code that processes the incoming data:
Private Sub formMain_Load(sender As Object, e As System.EventArgs) Handles Me.Load
Try
Dim listener As New System.Threading.Thread(AddressOf listen) 'initialize a new thread for the listener so our GUI doesn't lag
listener.IsBackground = True
listener.Start(CInt(IncomingPortString)) 'start the listener, with the port specified as a parameter (textbox1 is our port textbox)
Catch ex As Exception
txtSystemMessages_AddText(String.Format("Error in formMain_Load sub: {0}{1}", ex.Message.ToString, vbNewLine))
End Try
End Sub
Sub listen(ByVal port As Integer)
Try
Dim t As New TcpListener(IPAddress.Any, port) 'declare a new tcplistener
t.Start() 'start the listener
Do
Dim client As New ConnectedClient(t.AcceptTcpClient) 'initialize a new connected client
AddHandler client.gotmessage, AddressOf received 'add the handler which will raise an event when a message is received
AddHandler client.disconnected, AddressOf disconnected 'add the handler which will raise an event when the client disconnects
Loop Until False
Catch ex As Exception
txtSystemMessages_AddText(String.Format("Error in Listen sub: {1}{2}", ex.Message.ToString, vbNewLine))
End Try
End Sub
Sub received(ByVal msg As String, ByVal client As ConnectedClient)
Try
If Not clients.ContainsKey(client) Then
clients.Add(client, client.name.ToString) 'add the client to our hashtable
End If
Catch ex As ArgumentException
End Try
(The sub that processes the incoming data string "msg".)
End Sub
I'm at a complete loss to know what could be causing this issue, and a threading issue is all that I can think of. Could a different machine have different threading schemes? Any help would be greatly appreciated.
i have developed a very simple program using vs2010 as under and found exception like unable to connect to the remote server. i also tried to update the visual studio and reinstalled it but problem still exist.i tried to connect the visual studio by option online privacy statement under help menu but it even cant open google home page. i think there is a problem in visual studio in my pc or any port is closed or some thing else is going wrong.
Public Class Form1
Dim doc As HtmlDocument = New HtmlDocument
Dim a As HtmlDocument = New HtmlDocument
Dim web As HtmlWeb = New HtmlWeb
Private _loadURL As HtmlDocument
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
doc = web.Load("http://Dawn.com/") ' (connection exception occur at this point)
End Sub
End Class
I think your network connection is connected through the PROXY SERVER or behind the proxy server. So you've to configure proxy server settings first for accessing any website or internet resource. The code below may help you.
Dim o As New MyWebService.Name
Dim pr As New System.Net.WebProxy("100.0.1.1", 80)
pr.Credentials = System.Net.CredentialCache.DefaultCredentials
o.Proxy = pr
Dim ds As New DataSet
ds = o.GetMyData(Me.TextBox1.Text, "password")
Me.DataGridView1.DataSource = ds.Tables(0)
You've to modify it according to your proxy configuration. (you can see proxy server address in browser settings or options)
I have a url link that once you click on it, a txt file automatically downloads but I want to set the folder where this txt file downloads to be in the below desktop folder "C:\Users\User1\Desktop\Folder"
The below link opens the URL in a browser and downloads the file automatically to the "Downloads" folder as I am using Chrome. I would like to set the download folder via sql vb.net.
Below are the queries I tried but only the first one worked but downloaded to "Downloads" folder (very simple):
Private Sub UpdateBtn_Click(sender As Object, e As EventArgs) Handles UpdateBtn.Click
System.Diagnostics.Process.Start("URL")
End Sub
I also tried the below code but it gave me an error that I have to specify a file name - but I don't want it to work that way:
My.Computer.Network.DownloadFile("URL", "C:\Users\User1\Desktop\Folder", "", "", False, 500, True)
Another query I tested but nothing happened:
Dim wc As New Net.WebClient
Dim Path As String = Environment.GetFolderPath(Environment.SpecialFolder.DesktopDirectory)
wc.DownloadFileAsync(New Uri("URL"), Path)
Any help would be much appreciated.
Thank you all !
Marc
If it's just a text file you could use the WebClient to download it straight from your app and then have your app write it out to the user's hard drive (wherever you have permission of course).
Dim wc As New WebClient()
AddHandler wc.DownloadStringCompleted, AddressOf wc_DownloadStringCompleted
wc.DownloadStringAsync("URL")
Private Shared Sub wc_DownloadStringCompleted(sender As Object, e As DownloadStringCompletedEventArgs)
'add any error handling code
'...
File.WriteAllText("C:\Users\User1\Desktop\Folder\MyFile.txt", e.Result)
End Sub